oa Depositional Environment and Sequence Stratigraphy of the Neocomian Fahliyan Formation in the North Dezful Embayment, SW Iran

Fahliyan Formation (Neocomian) is one of the important hydrocarbon reservoirs of khami group in<br>south west of Iran. This Formation has 332m thickness in type section and mainly consist of carbonate<br>rocks. In this study,the Fahliyan Formation was investigated in subsurface section of AZN#B Well in<br>the north Dezful Embayment(with281m thickness). Lower boundary of Fahliyan Formation with Garau<br>Formation is continuous and the upper contact with Gadvan formation is conformable According to this<br>study 13 carbonate microfacies and one shaily facies were recognized which are grouped into four<br>facies associations micro facies group). These facies associations present platform to basin depositional<br>setting and are nominated as : A (Tidal-flat), B (Lagoon), C (Bar) and D (Open marine).<br>Based on available data set including cutting samples,thin sections and well log analysis, it seems the<br>Fahliyan Formation was deposited in a Carbonate shelf setting and the studied profile indicates the<br>shallowest part of the platform.Vertical succession of microfacies and relative depth changes of the<br>Fahliyan Formation led to identification of two third-order depositional sequence. The first sequence<br>includes HST only and the TST is in the Garau Formation. The upper boundary of this sequence is a<br>type 2 (SB2). The second sequence includes TST and HST,and upper boundary with The Gadvan<br>Formation is type 1 sequence boundary (SB1).